Ceramic coating compositions for providing decorative and functional coatings for glass, chinaware and the like are well known. In general, ceramic coating compositions are composed of a vehicle or medium, glass frit, and, optionally, pigment. Typically, the composition is in the form of a paste and applied to a substrate such as automotive or architectural glass by silk screening or other application technique. The coated substrate is then heated to volatilize the vehicle or medium, and/or fired to fuse the glass frit, thereby firmly bonding the coating to the surface of the substrate. The vehicle used in these paste compositions typically includes volatile organic solvents. As will be appreciated, such solvents are detrimental to the environment and have resulted in governmental regulations that require lowering the amounts of volatile organic compounds (VOC) in coating compositions. Therefore, a need exists in the art for ceramic coating compositions which have a reduced VOC content.
In an attempt to reduce VOC emissions, prior efforts have been made to formulate paste ceramic coating compositions based on high boiling solvents or curable acrylic monomers. However, because of certain practical issues, such solvents or mediums cannot be used as a primary vehicle or as an additive because they drastically change the drying time and application viscosity of the resulting composition. Accordingly, a need remains for a low VOC medium which still provides acceptable drying and application characteristics for a paste ceramic coating composition using the medium. This need is also applicable to other compositions that are used in firing processes such as glass enamels, glazes and electronic thick and thin films.